一例甲鱼急性死亡的病原菌分离、鉴定与药敏分析

Isolation,Identification and Drug Sensitivity Analysis of Pathogenic Bacteria from a Trionyx sinensis Acute Death

为了给甲鱼病害防控的合理用药提供技术支持,本研究自2018年4至5月采集了湖南常德某甲鱼养殖场急性死亡病样,进行了病原分离、鉴定与药敏分析。试验采用无菌穿刺接种法从濒临死亡的病鳖肝脏中分离出1株病原菌,命名为HTG。利用血琼脂平板对该病原菌进行毒力检测,结合形态观察与16S rDNA序列分析法进行鉴定,采用K-B纸片扩散法对病原菌进行药敏分析。毒力检测显示HTG在血琼脂平板上呈β溶血;16S rDNA序列分析表明HTG与Aeromonas hydrophila strain JCM 1027的16S rDNA基因的核苷酸序列同源,相似性为100%,结合形态特征将HTG鉴定为嗜水气单胞菌;药敏分析结果显示HTG对多西环素高度敏感(抑菌圈直径达30 mm)。根据药敏分析结果,建议该养殖场采用内服多西环素,辅以保肝护肝渔药对该病进行防控。

In order to provide technological data for the rational drug use for disease prevention and control of Trionyx sinensis,isolation,identification and drug sensitivity analysis of pathogenic bacteria from a Trionyx sinensis acute death in Changde were performed from April to May of 2018.A strain of pathogenic bacteria named HTG was isolated from the liver of the dying Trionyx sinensis by aseptic puncture inoculation.The virulence of the pathogenic bacteria was detected by blood agar plate.The pathogenic bacteria were identified based on morphology observation and 16S rDNA gene sequence analysis.The drug sensitivity tests were performed by Kirby-Bauer method.Virulence test indicated that the strain submitted β hemolysis.Phylogenetic analysis based on 16S rDNA sequence indicated that HTG were homology with Aeromonas hydrophila strain JCM 1027,the similarity was 100%.Combined with morphological characteristics and 16S rDNA sequence analysis,the HTG was identified as Aeromonas hydrophila.The results of drug sensitivity analysis showed that HTG was highly sensitive to doxycycline (the diameter of the inhibition zone was up to 30 mm).Based on the results of drug sensitivity analysis test,oral doxycycline and liver protective fishery drugs are recommended for the disease prevention and control.